00328nam a2200109 a 4500008004100000050001500041100002200056245008900078260003200167300001000199350000900209120416s1971    ||||||||||||||||| ||    u  aQA 431 Spi  aSpiegel, Murray R10aSchaum's outline problems of calculus of finite differences and difference equations  aNew YorkbMcGraw-Hillc1971  a259p.  a0.00